(1) At first glance, rock crystals are often influenced by the environment and always contain some impurities. When you look at the sun, you can see faint or even tiny stripes or catkins. Fake crystals are mostly made of inferior crystal slag and glass slag. After polishing, coloring and imitation, there are no uniform stripes and catkin-like substances.
(2) Lick your tongue: Even in the dog days of hot summer, licking the surface of the crystal stone with your tongue will feel cold and cool. Fake crystals are not cool.
(3) Illumination: When the crystal is placed vertically in the sun, it can emit beautiful light from any angle. Fake crystals can't.
(4) Hardness: The hardness of the crystal is very high, and it will leave no trace when lightly scratched with gravel on the jewelry; If there are streaks, it is a fake crystal.
(5) Inspection with a polarizer: the rock crystal rotates 360 degrees under the polarizer, with four bright and four dark changes, while the fake crystal does not change.
(6) Check with dichroism: natural amethyst has dichroism, while fake amethyst has no dichroism.
(7) Magnifier inspection: under the transmitted light, the bubbles that can be found can be basically classified as pseudocrystals.
(8) Check with hair: If the crystal is placed on a hair, the human eye can see the double shadow of the hair through the crystal, it is a rock crystal, mainly because the crystal has birefringence.
(9) Test with a thermal conductivity meter: set the thermal conductivity meter to 4 squares of green to test the gem, and the rock crystal can rise to 2 squares of yellow, while the false crystal does not rise, and when the area is large, it will rise to 1 square yellow.
Discrimination between natural and synthetic crystals
Another characteristic that distinguishes crystal stone from artificial crystal is its luster. The surface of rock crystal ornaments presents grease luster, while the surface of synthetic crystal ornaments presents glass luster. At present, there is no synthetic crystal with grease luster.
Although crystal is not a precious gem, it is more and more loved by men, women and children all over the world because of its unparalleled medical effect and low price. As a crystal lover, everyone wants to have all kinds of crystals, whether natural or synthetic, but he must want to know whether his crystal is synthetic or natural.
At present, colorless crystal necklaces and tea crystal necklaces on the market can be described as natural and synthetic, while colored crystal necklaces are mostly synthetic crystals. There are fewer real natural colored crystals, and even fewer are used to make necklaces.
The biggest feature of synthetic crystal is that it has a daughter nucleus. Synthetic crystals are easier to judge if they have crystal nuclei, because crystals and generally colorless long plate columns have obvious boundaries with the surrounding synthetic crystals. But recently, some colorless synthetic crystals on the market, the crystal nucleus and synthesis are colorless, and there are some natural inclusion characteristics in the crystal nucleus or some bubbles between the crystal nucleus and the synthetic crystal, which makes some experienced people easily mistake them for rock crystals. If you look closely, you will find what kind of inclusions only exist in children and hosts, and there is a feeling of being blocked around them by an invisible wall. The bubbles between the crystal nucleus and the synthetic crystal are distributed along the crystal nucleus wall, forming a "bubble wall" which is parallel to each other. Some bubbles are tadpole-shaped, and the head is arranged outward towards the wall and tail. In rock crystals, groups of inclusions are often arranged along a surface, but this surface is often single and fluctuating, and the inclusions that make up this surface are mostly binomial inclusions, not just bubbles. The difference between the two is obvious.
The second characteristic of synthetic crystals, especially color synthetic crystals, is the uniformity of smoke color. The color of the whole necklace is relatively uniform, especially the yellow crystal series and the brown-black synthetic crystal. However, natural yellow is often uneven with brown and black crystals. Rock crystals are not only uneven in color, but also often have a tawny hue (except tawny crystals). What's more interesting is that at night, under the white orange lamp, the brown crystals are exactly like brown crystals. If mixed with brown crystals, the environment is difficult to identify. The synthetic topaz I have seen is pure and uniform in color, with some dark tones, but it has no tea tone and will not change color under the white orange lamp at night.
It is worth noting that in synthetic amethyst, some well-oriented deep purple flakes often appear, which is easily reminiscent of the characteristics of irregular flake color groups in natural amethyst. The biggest difference between the two is that the purple clusters in the synthetic amethyst are arranged in parallel sheets, with little difference in size and shape. Purple flakes are compared to floating "purple cloth patches", while purple clusters in natural amethyst can be regarded as floating "purple smoke clusters". This is the main difference between the two.
Natural colored crystals, especially amethyst, have another feature, that is, hexagonal bands like sapphire. It is worth noting that in some synthetic green crystals, parallel bands often appear, and the bands develop parallel layer by layer along the daughter crystal nucleus. I have also seen a synthetic green crystal necklace, which appears in the yellow-green countryside, much like a ribbon of rock crystal. In addition, there are some brown translucent solid impurities in it, which can be easily mistaken for natural green crystals. However, the bands formed by synthetic crystals are distributed in parallel along the subnuclear wall, and the angles between objects are straight. The ribbons of the whole necklace are the same, and the width and color of each ribbon are the same, giving people an unnatural feeling of being too "in step".
The third characteristic of synthetic crystal is cleanliness. There are inclusions and sponges in rock crystals, and the synthetic crystals are crystal clear. Some synthetic crystals have bubbles or some solid impurities. Recently, triangular long tubular pores often appear in some synthetic crystals, and there are green fiery red powders in these pores. This kind of long tube is characterized by parallel arrangement in one direction, triangular cross section, uneven green and fiery red powder distributed along the wall, often empty in the middle, and the end of the long tube is often pointed. The real natural hair crystal is a crystal containing tourmaline, actinolite, rutile and other minerals, which has a gas crystal shape, such as the "bamboo-like" shape of actinolite. They are wrapped in crystals, randomly arranged without direction, with different names for thickness and length, and often accompanied by inclusions and cotton inherent in rock crystals.
I like that kind of crystal clear, but I'm afraid to buy fake inferior products. Why not learn a little discrimination?
Specific gravity: too light must be false, so that imitations such as glass, plastic and pressed particles can be excluded. However, there are many crystals on the market now, the weight of which is similar to that of rock crystal, so it is not easy to find the authenticity by hand.
Refractive index: most people like to look at the crystal under the lamp, so they can't judge whether the crystal is true or not, but only the grade of the crystal, because the refractive index of the crystal is very high. We can put the crystal in a dark place. The color of the rock crystal will be very bright, and the color of the crystal will be dim, lacking the sense of "spirit" and only slightly bright. You can use natural white crystal and glass to compare and feel it.
Price: Crystal cultivation is similar to natural gem-grade crystal, that is, the crystal is extremely transparent, with almost no stone particles, but the price is very different. Usually, crystal training bracelets will be cut into sections. Crystal is transparent, but the price is generally not too high. However, if it is really a natural gem, the price must be above 100 yuan, depending on the size of the crystal.
Color difference: Crystal has color difference, so every part of a crystal can't have a uniform color, such as topaz, which is rare in the market. Natural topaz can be identified by putting it in water. Natural topaz is uneven in color in water. Usually one color radiates to the whole crystal, which is yellow, so the crystal color is absolutely uniform.
Others: it feels very cold, and the crystals with stone lines are basically not fake.
Inclusions: If there are inclusions, there will be no fakes, so you can buy crystals with inclusions such as hair crystals and ghosts with absolute confidence, because the cost of forging such things is very expensive and laborious, and the effect is easy to see through.
There are generally the following kinds of fake crystals on the market: 1. Glass products. Melted crystal 3. Lead glass. Synthetic crystals. Regenerate crystals (crystal culture).
A simple polarizer is used to distinguish between true and false crystals. It is a refraction clip composed of upper and lower polarizers, which can distinguish glass from crystal. Because glass is an isotropic body, you can turn it any way if you put it in the middle of the refraction clip, and the fake crystal is always black; If you rotate 360 degrees in the middle of the refraction clip, there will be four changes in the laws of light and shade, undoubtedly crystal.
At present, there are colorless crystals, amethyst, topaz, smoky crystals and hair crystals used to make gems.
Crystal stone is colorless and transparent, and is used to make crystal balls, jade carving products and crystal Ding Ting.
Amethyst is a kind of deep purple-lavender crystal, which is mainly used to make ring faces and jade carving products.
Shi Ying light gray crystal, mainly used for jade carving.
Orange and brown crystals are mainly used to make gem ring.
Hair crystal hair crystal contains inclusions such as amphibole and tourmaline filled with fine fibers.
I. Physical and chemical properties
Chemical composition of crystalline silica. Tripartite system. The crystal is a columnar crystal, and the cone head is composed of hexagonal double push and hexagonal column.
Color: colorless, purple, yellow, brown, gray-black. Transparent.
Gloss: glass luster.
The refractive index is 1.544- 1.553 and the birefringence is 0.09.
Hardness 7.
The density is 2.66 g/cm3.
Shell fracture.
Amethyst has a weak to clear dichroism.
Second, the characteristics of naked eye wetting
At present, there are many kinds of crystals on the market, including natural colorless crystals, topaz, smoky crystals and amethyst. Artificially colored sky blue crystal, orange crystal, purple crystal and bicolor crystal; Synthetic colorless crystals and purple crystals. Because they look basically the same, they are not very different from each other.
(A) the difference between natural colorless crystals and synthetic colorless crystals
Natural colorless crystals and synthetic colorless crystals are mainly used to make beaded top dragonflies and crystal balls, and the market is unprecedented. Their main differences are inclusiveness and transparency.
In most crystal necklaces or crystal balls with inclusions, there is always a flaw. If you immerse them in water or let them out, you will see with the naked eye that some beads or crystal balls have a small amount of reflective surfaces or flocculent gas-liquid inclusions in some places. However, there are few inclusions in the synthetic crystal, and the interior is dry and clear, and almost no defects can be seen.
Transparent rock crystal, blue and clear, clear inside. For example, a faceted beaded necklace, placed in a white porcelain basin filled with water, can see the periphery of each bead, with clear water in the middle, as if nothing existed. The intraocular lens is naturally transparent, but after being put into water, the periphery of the beads is clear, but the middle is not as clear as the surrounding water like the rock crystal beads, and the existence of the beads can be felt.
(2) The difference between natural amethyst and synthetic amethyst.
There are two differences between natural amethyst and synthetic amethyst.
Color and its distribution The color of natural amethyst is bright and soft, but the distribution is uneven. When the main stone is put into the water, you can see purple patches or flat ribbons. Synthetic amethyst has different shades of purple, which is generally uniform, accompanied by gray tones, and the color is dull. Even if the color of some products is uneven, it changes gradually according to the light, and purple spots and straight ribbons are not visible.
The natural amethyst of inclusions shows tiger-pattern healing cracks or hollow flocculent gas-liquid inclusions. However, synthetic amethyst rarely sees inclusions, and occasionally only thin-plate colorless seed crystals or white bread crumbs can be seen.
(3) The difference between rock crystal and color-changing crystal.
Rock crystals can turn brown, brownish black, golden yellow, purple and bicolor after being bombarded by ion accelerator or briefly irradiated by radioactivity. Except for bichromatic crystals, other colored crystals are uniform in color, and no color groups or ribbons can be seen when put into water. The changed crystal color is always accompanied by a gray tone, and the color is not as bright as the rock crystal.
So far, we haven't seen any kind of crystal with two colors at both ends in nature, but only a bicolor crystal with brown and purple mixed together, which is produced in Bolivia. At present, the two-color crystals distributed at both ends of the fixed stone on the market are all synthetic crystals that have changed color. Color-changing synthetic crystals are brownish green and brownish red at both ends of chamotte, or light blue and reddish. The boundary between the two colors is straight and clear, and several straight stripes are seen on the contact belt.
(4) The difference between crystal and topaz.
Colorless or colored sky blue and orange crystals are very similar in appearance to colorless or colored sky blue and orange topaz. The only difference with the naked eye is that the reflection effect of the inner facet at the bottom of faceted crystal is far less than that of topaz. Although the reflection of crystal is bright, it has no mirror effect. The reflection surface of topaz is as bright and white as a small mirror.
(5) The difference between a natural crystal ball and a glass ball
At present, there are two colors of imitation crystal glass, one is colorless glass (fused crystal) as crystal ball imitation colorless crystal; One is amethyst-like purple glass.
Natural crystal ball is clear and transparent. When put into water, gas-liquid inclusions or flocculent inclusions may be seen in small places, which will be cold when touched by hand. Although the glass ball made of melted crystal is transparent, it is not clear, as if it is warm when touched by hand with milky light, and circular bubbles may be seen when put into water. In addition, the rock crystal has birefringence, even if the birefringence is only O. OO9, with the increase of the sphere, the two refracted rays will gradually separate. If the crystal ball is pressed on a newspaper printed with small fonts and viewed vertically from the top of the ball, there will be two phenomena: one is that the font is enlarged and the handwriting is clear (parallel to the light direction of the crystal). If you rotate the sphere 90 degrees, besides enlarging the font, there are double shadows in the handwriting. The bigger the sphere, the clearer the double shadow font. Because the glass ball is an isotropic body, the handwriting observed perpendicular to the ball in any direction is clear, but it is not the most double.
Amethyst-like purple glass, transparent and flawless, even purple, without purple stripes or spots. When you put them in water or observe them with an IO magnifying glass, you may see round bubbles.
Observing inclusions is also the best way to distinguish between crystal stone and artificial crystal.
Crystal balls are very popular in the former market. As far as their materials are concerned, they are mainly fused crystal glass and crystal. Their prices vary greatly. How to distinguish them is not difficult. It can be distinguished by a deflectometer in a professional laboratory. But in general, in addition to observing the clarity of the sphere and a small amount of inclusions with the naked eye, we should also look for the phenomenon that the ghost of rock crystals can blur the handwriting from different directions.
The prices of raw materials of Xiaoyan crystal and synthetic crystal are not much different, and their physical and chemical properties are basically the same. If it is used for packaging, there is no need to be too demanding to discuss its causes. The identification method is that they have different inclusions.
Five-color crystals are produced in all countries. The main producers of amethyst are Brazil, Uruguay, South Africa and Madagascar, as well as China, India and the United States.